It depends on what program that you are launching when you see this message. For example, if you are launching Microsoft Word to view or edit a document, and suddenly you see this, you should block this. A document is not supposed to run anything. If you are running a utility, or a software from a company that you trust, and you see this, you may allow it to run.

That is the problem in that I am not aware of running anything special though I may have had TOR browser open at the time. However I use that a lot and don't normally see any issue, indeed I have it running now and the message is not appearing. It appeared many times over the space of 2 - 3 days but now seems to have stopped for the time being. Could something like this indicate someone trying to take control of my computer? I have run a full scan but it comes up clean.

I guess there is not much to do unless it happens again. Usually in the past when I have seen messages like this there has been something in it to indicate what is triggering it - for example dropbox action sometimes has in the past but this one gives no clue. The worrying thing is that I have only recently completey refreshed my windows installation removing all programmes and content on my system and program software drive.

If it is running out of nowhere, it could be an attack, although sometimes it may not be the case. Probably something from web, since you are opening a browser. It looks like it tried to disable unused Windows sharing (Samba protocol). It triggered using fileless method, so Antivirus is usually difficult to catch this. When you try to scan it, there may be no trace any more.